The present invention relates to structure for attaching dozer blades to work vehicles and more specifically relates to a structure which is particularly suited for attaching a dozer blade to an excavator.
The idea of making an excavator more versatile by providing it with a dozer blade is known as is evidenced by U.S. Pat. No. 4,315,636 granted to M. Nakagawa on Feb. 16, 1982. The structure disclosed in the patent for attaching the blade to the excavator is quite rudimentary and merely shows a blade fixed rigidly with a frame which is vertically swingably connected to the excavator and a lift actuator for selectively causing vertical movement of the frame. No provision is made for angling, tilting or pitching the blade relative to the frame. Thus, the blade can only perform the most basic of tasks.
While it has long been known to attach dozer blades to crawler tractors by structures which provide for angling, tilting and pitching the dozer blade, these structures lack overall simplicity and are not suitable for connection to an excavator. For example, U.S. Pat. No. 3,991,832 granted to Cooper on Nov. 16, 1976 illustrates one type of structure which comprises a C-frame vertically pivotally mounted to a vehicle main frame and a blade universally connected at its center to the C-frame. A first pair of actuators are operable for raising and lowering the C-frame, a second pair of actuators are operable for angling or pitching the blade and a third actuator for tilting the blade. These blade motions are about its universal connection with the C-frame and the distance the blade is required to be mounted forwardly for providing adequate angling clearance is somewhat excessive. U.S. Pat. No. 3,941,195 issued to Stedman on Mar. 2, 1976 discloses a design which permits the blade to be close coupled to a crawler tractor by using separate push arms connected to the back of the blade and a transverse brace coupled between the tractor frame and one of the arms. However, no means for angling the blade is apparent.